Solid-state image pickup apparatus and fabricating method thereof

ABSTRACT

A solid-state image pickup apparatus having hermetic seal portion capable of packaged in a smaller size by a simple construction and fabricated with high precision at wafer level is constructed such that an epoxy-type resin sheet having opening portion only at light-receiving portion is adhered to solid-state image pickup device chip by an adhesive and a transparent member capable of becoming a flat-plate portion is adhered onto the epoxy-type resin sheet by means of an adhesive.

This application claims benefit of Japanese Application No. 2000-66214filed in Japan on Mar. 10, 2000, the contents of which are incorporatedthis reference.

BACKGROUND OF THE INVENTION

The present invention relates to solid-state image pickup apparatus andfabricating method thereof having a solid-state image pickup device chippackaged in a hermetic seal.

A conventional solid-state image pickup apparatus having light receivingsensor chips such as a solid-state image pickup device chip in ahermetically sealed package is generally constructed as shown in FIG. 1.In particular, a solid-state image pickup device chip 101 is die-bondedto a package 102 for example of ceramics and a bonding wire 103 is usedto achieve predetermined electrical connections between the solid-stateimage pickup device chip 101 and package 102. A space from the surfaceof the device chip 101 is provided by using step 104 formed at edgeportions of package 102 and a hermetic seal is achieved by adhering aglass lid 105 thereto to construct the solid-state image pickupapparatus. It should be noted that numeral 106 in FIG. 1 denotes anexternal lead.

In solid-state image pickup apparatus having such construction, use ofpackage 102 and glass lid 105 for hermetically sealing the entiresolid-state image pickup device chip resulted in an increased packagingsize and thus had been difficult to be applied to the fields wheresmaller package size was required.

To eliminate such disadvantage, the present applicant had proposedsolid-state image pickup apparatus constructed as disclosed in Japanesepatent laid-open application Hei-7-202152. A sectional view of suchsolid-state image pickup apparatus is shown in FIGS. 2 and 3. In FIG. 2,only the light-receiving area on the solid-state image pickup devicechip 101 is hermetically sealed by means of a sealing member whichincludes a flat-plate portion 107 made of a transparent member and aframe portion 108 integrally formed therewith at a lower surface edgethereof. Glass, quartz, sapphire, transparent resin or the like is usedas the transparent member for constituting the flat-plate portion 107.In the solid-state image pickup apparatus shown in FIG. 3, on the otherhand, instead of integrally forming a hermetic seal portion, aflat-plate portion 109 and a frame portion 110 are adhered to each otherto constitute the hermetic seal portion. Here frame portion 110 may beconstituted by such inorganic materials as ceramics, glass, silicon orsuch metal as Kovar or 42-alloy. Further, it is also possible that anepoxy, phenol, or silicone resin may be printed or pattern-formed byphotolithography on the surface of the solid-state image pickup devicechip 101 to form the frame portion 110.

By constructing solid-state image pickup apparatus in this manner, asmaller size packaging thereof is possible and, especially in asolid-state image pickup apparatus having a micro-lens, the solid-stateimage pickup apparatus can be achieved without degrading the lightconverging capability of the micro-lens even when such opticalcomponents as a filter, lens, prism, etc., is adhered to the surface ofthe hermetic seal portion. Further, fabrication method has also becomesimpler, since hermetic seal portions can be formed at once for all of alarge number of solid-state image pickup device chips in a wafer.

The previously proposed solid-state image pickup apparatus as describedabove, however, has the following problems to be solved. First, thestructure of the integrally formed, hermetic seal portion as shown inFIG. 2 requires an integral forming of the hermetic seal portion havinga flat-plate portion and a frame portion by using such transparentmaterial as glass. Precision in processing is thus required anddifficulties such as an increased the amount of work in fabrication areforeseen.

Further, the method of constructing the hermetic seal portion byadhering flat-plate portion and frame portion to each other as shown inFIG. 3, especially the method of constructing the frame portion by meansof a pattern forming of resin, requires the processing steps of forminga resinous pattern, i.e., application of the resin onto a wafer,printing or photolithography, developing and etching. There is thus aproblem that the number of processing steps is increased.

Furthermore, a more serious problem presumably occurs with thistechnique when the solid-state image pickup apparatus has a micro-lens.This is because a micro-lens, usually, is formed also from a resin. Forexample, after applying a resin over the entire surface of a wafer, theprocessing steps of patterning and etching of the frame portion must beperformed before the resin cures. If etching is performed before thecuring of the resin, however, the resin capable of becoming the frameportion is also etched away similarly as the portion of resin to beremoved and there is a possibility that a sufficient frame is notformed. If etched after the curing of the resin, on the other hand,though a desired shape for the frame is formed, there is a possibilitythat the micro-lens is etched away at the same time of the etching ofthe unnecessary portion of resin to be removed due to the fact that themicro-lens is also made of a resin.

As the above, those previously proposed are with problems in thefabrication method or the reliability of hermetic seal portion, eventhough smaller size packaging is possible and hermetic seal portions canbe formed at once for all chips in a wafer.

SUMMARY OF THE INVENTION

To eliminate the above problems, it is a main object of the presentinvention to provide a solid-state image pickup apparatus which can bepackaged in a relatively small size and at the same time has a simpleconstruction and a reliable hermetic seal portion.

In accordance with the invention, there is provided a solid-state imagepickup apparatus fundamentally including: a solid-state image pickupdevice chip; and a hermetic seal portion provided over the solid-stateimage pickup device chip having a flat-plate portion formed of atransparent member and a frame portion adhered to a lower surface edgeportion of the flat-plate portion, the frame portion of the hermeticseal portion comprising an epoxy-type resin sheet.

By constructing as the above, the solid-state image pickup apparatus canbe achieved by a simple construction capable of downsizing at the sametime of having a highly reliable hermetic seal portion. The above mainobject is thereby accomplished.

It is another object of the invention to provide a solid-state imagepickup apparatus having a hermetic seal portion based on a simplerconstruction not requiring an adhesive.

In a further aspect of the invention, the epoxy-type resin sheet of theframe portion of the hermetic seal portion of the solid-state imagepickup apparatus of the above fundamental construction has an adhesiveproperty.

By constructing as the above, an adhesive becomes unnecessary in theforming of hermetic seal portion so that the hermetic seal portion canbe made easily using a simple construction. The above object is therebyaccomplished.

It is yet another object of the invention to provide a solid-state imagepickup apparatus in which shielding of unwanted rays of light atsolid-state image pickup device can be effected without providing aseparate member for shielding light.

In a further aspect of the invention, the epoxy-type resin sheet of theframe portion of the hermetic seal portion of the solid-state imagepickup apparatus of the above fundamental construction has a function ofshielding light based on coloring or the like.

By constructing as the above, the frame portion of hermetic seal portionis capable of shielding unwanted rays of light so that adverse effectsdue to stray light or reflection on solid-state image pickup device chipcan be prevented without providing a separate member for shieldinglight. The above object is thereby accomplished.

It is still another object of the invention to provide an optimumelectrical connection structure between solid-state image pickup devicechip and an external terminal in solid-state image pickup apparatushaving a hermetic seal portion.

In a further aspect of the invention, the solid-state image pickupapparatus of the above fundamental construction has a wiring regionformed from an electrode pad provided on the solid-state image pickupdevice chip to a side surface or from the electrode pad to a reversesurface of the solid-state image pickup device chip through the sidesurface so that an external terminal can be electrically connected tothe wiring region.

By constructing as the above, an optimum electrical connection structurecan be achieved between the solid-state image pickup device chip and theexternal terminal. The above object is thereby accomplished.

It is another object of the invention to provide fabricating method ofsolid-state image pickup apparatus capable of readily forming a hermeticseal portion with high registration accuracy on solid-state image pickupdevice chip.

In accordance with a further aspect of the invention, a fabricatingmethod of solid-state image pickup apparatus including a solid-stateimage pickup device chip and a hermetic seal portion provided over thesolid-state image pickup device chip having a flat-plate portion formedof a transparent member and a frame portion adhered to a lower surfaceedge portion of the flat-plate portion includes the steps of: for anentire wafer having a large number of solid-state image pickup devicechips formed thereon, integrally forming hermetic seal portion having aflat-plate portion made of a transparent member and a frame portionformed of an epoxy-type resin sheet adhered to a lower surface edgeportion of the flat-plate portion correspondingly to respectivesolid-state image pickup device chips; separating the wafer having theintegrally formed hermetic seal portion thereon into solid-state imagepickup device chips each having an individual hermetic seal portion.

By using such processing steps, hermetic seal portions can be formed atonce on respective solid-state image pickup device chips in a wafer.Accordingly, it becomes possible to readily fabricate a solid-stateimage pickup apparatus having a hermetic seal portion precisely oversolid-state image pickup device chip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of solid-state image pickup apparatus packagedwith a conventional hermetic seal.

FIG. 2 shows construction of solid-state image pickup apparatus having ahermetic seal portion previously proposed by the present applicant.

FIG. 3 shows another construction of solid-state image pickup apparatushaving a hermetic seal portion previously proposed by the presentapplicant.

FIG. 4 is a top view showing an embodiment of solid-state image pickupapparatus according to the invention.

FIG. 5 is a sectional view of the embodiment shown in FIG. 4.

FIG. 6 shows fabrication process to explain an example of fabricatingmethod of solid-state image pickup apparatus according to the invention.

FIG. 7 shows fabrication process continued from the fabrication processshown in FIG. 6.

FIG. 8 shows an example of packaging of solid-state image pickupapparatus according to an embodiment of the invention.

FIG. 9 shows an example of the manner of bringing an electrode out frompad portion of the solid-state image pickup apparatus according to anembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some embodiments according to the invention will now -be described.FIGS. 4 and 5 are a top view and a sectional view, respectively, showingan embodiment of the solid-state image pickup apparatus according to theinvention. Referring to these figures, denoted by numeral 1 is asolid-state image pickup device chip; an epoxy-type resin sheet 4 havingopening portion 3 only at the portion corresponding to a light-receivingportion 2 of the solid-state image pickup device chip 1 is adhered tothe solid-state image pickup device chip 1 by means of an adhesive 5.

A solid-state image pickup apparatus is then constructed by adhering atransparent member 6 onto the epoxy-type resin sheet 4 by means ofadhesive 5. In this construction, therefore, the epoxy-type resin sheet4 becomes a frame portion and the transparent member 6 becomes aflat-plate portion in forming a hermetic seal portion. It should benoted that, in FIG. 4, denoted by numeral 7 a, 7 b are peripheralcircuit portions for the light-receiving portion 2 of the solid-stateimage pickup device chip 1.

Here, opening 3 of epoxy-type resin sheet 4, i.e., a portion to behermetically sealed is extended only over the light receiving portion 2of solid-state image pickup device 1. It is however also possible toprovide the hermetic seal portion for the entire solid-state imagepickup device chip including the peripheral circuit portions 7 a, 7 b(excluding peripheral edge portions). A hole on the epoxy-type resinsheet 4 must be provided in advance for the portion corresponding to theregion to be hermetically sealed. The transparent member 6 capable ofbecoming the flat-plate portion is preferably of glass, quartz,sapphire, transparent resin or the like. An epoxy- or silicone-typeresin is preferably used for the gluing between the epoxy-type resinsheet 4 capable of becoming a frame portion and the solid-state imagepickup device chip 1 and the transparent member 6 capable of becoming aflat-plate portion.

The fabricating method of a solid-state image pickup apparatus havingsuch construction is very simple and only a summary of the processingsteps thereof will be described below. First, as shown in FIG. 6,adhered by means of adhesive 5 onto wafer 8 having a large number ofsolid-state image pickup device chips formed thereon is an epoxy-typeresin sheet 4 a extended over the entire wafer and having previouslyprovided openings 3 at the portions corresponding to desired region ofrespective solid-state image pickup device chips. Subsequently, as shownin FIG. 7, a transparent member 6 a such as of-glass capable of becomingflat-plate portion is integrally-adhered to the entire wafer by means ofadhesive 5 for the entire surface on the resin sheet 4 a. Lastly, asolid-state image pickup device chip having a hermetic seal portion asshown in FIG. 5 is completed by means of dicing along scribed lines 9.

Here, micro-lens or color filter for example may be formed on-chip or beformed by bonding or the like on the solid-state image pickup devicechip. Further, the alignment mark at the time of fabricating solid-stateimage pickup device chip wafer can be used for the adhering of resinsheet 4 to wafer 8 and of transparent member 6 a capable of becomingflat-plate portion to the resin sheet 4 a. Since an accurateregistration becomes possible, a hermetic seal portion can be formedprecisely on the solid-state image pickup device chip.

It should be noted that, in this embodiment, an adhesive is used for theadhering of the epoxy-type resin sheet capable of becoming frame portionto the wafer and for the adhering of the transparent member capable ofbecoming flat-plate portion to the epoxy-type resin sheet. If anadhesive property is previously imparted to the epoxy-type resin sheet,however, the adhesive becomes unnecessary and the solid-state imagepickup device chip, the resin sheet capable of becoming frame portionand the transparent member capable of becoming flat-plate portion can bereadily adhered to each other. Accordingly, it becomes possible to morereadily form the hermetic seal portion. As the epoxy-type resin sheethaving an adhesive property, there is one available on the market in theform of a sheet with an epoxy resin applied on the both surface of aglass fiber layer thereof so that it becomes capable of adhering whenheat and pressure are applied. Such resin sheet can be used.

Further, by using an epoxy-type resin sheet colored for example in blackso as to shield light, the resin sheet capable of becoming the frameportion of the hermetic seal portion serves as a shield from light. Itis thereby possible to shield unnecessary rays of light impinging on thesolid-state image pickup device chip. Accordingly, an adverse effect forexample due to stray light or reflection on the solid-state image pickupdevice chip can be prevented.

A description will now be given with respect to packaging of thesolid-state image pickup apparatus constructed as the above and themanner of bringing out electrodes from pad portion thereof. FIG. 8 showsan example of packaging. The solid-state image pickup device chip 1 isdie-bonded to package or substrate 10. Packaging is achieved by usingbonding wire 11 to provide predetermined connections between a padportion 1 a of solid-state image pickup device chip 1 and the package orsubstrate 10. Though this construction suffices as it is, the peripheralportion including the bonding wire connecting portion other than thehermetic seal portion may also be sealed as shown in the figure by meansof sealing resin 12. Provided that, in this construction, the epoxy-typeresin sheet 4 capable of becoming the frame portion of hermetic sealportion must be formed with excluding pad portion 1 a of the solid-stateimage pickup device chip 1. Here, as the technique for removing resinsheet at the pad portion, a photosensitive epoxy resin sheet can be usedso that it be readily removed for example by means of etching bypatterning it based on ordinary photolithography after the adhering ofthe resin sheet onto the wafer as shown in FIG. 6.

FIG. 9 shows an example of bringing out electrodes from pad portion. Awiring region 13 is formed from pad portion 1 a to a chip side surface 1b or from the pad portion 1 a to a reverse surface 1 c on thesolid-state image pickup device chip 1 through the chip side surface 1b. It is furthermore possible to provide a separate electrode pad on thereverse surface wiring region so as to be connected to a board or thelike by means of a bump or the like. If such wiring region 13 is formed,it is not necessary to remove the portion of pad of the resin sheet 4capable of becoming frame portion of the hermetic seal portion. Itsuffices to form a resin sheet over the pad portion so that thelight-receiving area or entire chip is hermetically sealed.Alternatively, an external lead (not shown) for example may be connectedto the wiring region 13 on the chip side surface 1 b so as to achieve anelectrical connection with an external terminal.

By using the structure as shown in FIG. 9, packaging becomes unnecessaryand the solid-state image pickup device chip can be directly mounted onvarious circuit boards such as a circuit board having a signalprocessing circuit formed thereon. Further, by the wiring region orelectrode pad provided on the reverse surface of the solid-state imagepickup device chip, it can be readily bonded or adhered to asemiconductor chip having a signal generating circuit or signalprocessing circuit thereon. Accordingly, it becomes possible to readilymake a laminated solid-state image pickup apparatus where a solid-stateimage pickup device chip, signal processing circuit, etc., areintegrally formed. A further downsizing thus can be achieved of thesolid-state image pickup apparatus including peripheral circuits.

It should be noted that the packaging in FIG. 8 and the manner ofbringing out electrode from pad portion in FIG. 9 have been shown by wayof examples only. The present invention is not limited to these andvarious modifications thereof are naturally possible without departingfrom the spirit of the invention.

As has been described by way of the above embodiments, according to theinvention, a solid-state image pickup apparatus having a hermetic sealportion can be achieved as capable of downsizing by a simpleconstruction. Further, it is possible according to the invention toprovide a solid-state image pickup apparatus having a hermetic sealportion with a simple construction without requiring an adhesive.Further, it is possible according to the invention to provide asolid-state image pickup apparatus having a hermetic seal portioncapable of preventing an adverse effect due to stray light or reflectionon solid-state image pickup device chip without providing a separatemember for shielding light. Further, it is possible according to theinvention to provide a solid-state image pickup apparatus having ahermetic seal portion in which an optimum electrical connectionstructure can be obtained between solid-state image pickup device chipand an external terminal. Further, it is possible according to theinvention to readily fabricate a solid-state image pickup apparatushaving a hermetic seal portion precisely on solid-state image pickupdevice chip, since hermetic seal portions are formed at once over therespective solid-state image pickup device chips in a wafer.

What is claimed is:
 1. A solid-state image pickup apparatus comprising:a solid-state image pickup device chip; and a hermetic seal portionprovided over the solid-state image pickup device chip having aflat-plate portion formed of a transparent member and a frame portionadhered to a lower surface edge portion of the flat-plate portion, theframe portion of said hermetic seal portion comprising an epoxy-typeresin sheet adhered directly onto said solid-state image pickup devicechip.
 2. The solid-state image pickup apparatus according to claim 1,wherein the epoxy-type resin sheet of the frame portion of said hermeticseal portion has an adhesive property.
 3. The solid-state image pickupapparatus according to claim 1, wherein the epoxy-type resin sheet ofthe frame portion of said hermetic seal portion has a function ofshielding light based on coloring or the like.
 4. The solid-state imagepickup apparatus according to claim 2, wherein the epoxy-type resinsheet of the frame portion of said hermetic seal portion has a functionof shielding light based on coloring or the like.
 5. The solid-stateimage pickup apparatus according to claim 1, wherein a wiring region isformed from an electrode pad provided on said solid-state image pickupdevice chip to a side surface of said solid-state image pickup devicechip or from the electrode pad to a reverse surface thereof through theside surface so that an external terminal can be electrically connectedto the wiring region.
 6. The solid-state image pickup apparatusaccording to claim 2, wherein a wiring region is formed from anelectrode pad provided on said solid-state image pickup device chip to aside surface of said solid-state image pickup device chip or from theelectrode pad to a reverse surface thereof through the side surface sothat an external terminal can be electrically connected to the wiringregion.
 7. The solid-state image pickup apparatus according to claim 3,wherein a wiring region is formed from an electrode pad provided on saidsolid-state image pickup device chip to a side surface of saidsolid-state image pickup device chip or from the electrode pad to areverse surface thereof through the side surface so that an externalterminal can be electrically connected to the wiring region.
 8. Thesolid-state image pickup apparatus according to claim 4, wherein awiring region is formed from an electrode pad provided on saidsolid-state image pickup device chip to a side surface of saidsolid-state image pickup device chip or from the electrode pad to areverse surface thereof through the side surface so that an externalterminal can be electrically connected to the wiring region.